Protective wrapping for elongated member

ABSTRACT

A protective wrapping for an elongated member of generally circular cross section, and particularly an abrasion resistant wrapping to protect marine cables and conduits. The wrapping is a helically oriented element formed of laminations preventing it from being opened outwardly and away from the protected cable, but allowing the cable to flex. The wrapping can be installed by placement crosswise on the cable and winding it about the cable to seat successive turns. Clamps, or a helical filler located between turns of the element, are used to axially extend the wrapping to effect a tight grip upon the protected cable.

l United States ae 1 1 3,762,982

Whittington Oct. 2, 1973 {54] PROTECTIVE WRAPPING FOR 3,500,867 3/1970Elson 138/125 MEMBER 212.1 22: 3:22: 321:1;

, ny s Inventor: Richard Whittingmn, g 1,249,038 10 1917 Dabney 138/110Beach, Calif.

[73] Assignee: Whitlock, llnc., Long Beach, Calif. Prim ry min -AlfredL- Leavitt Assistant ExaminerCaleb Weston [22] June 19711Attorney-Fulwider, Patton, Rieber, Lee & Utecht [2i] -Appl. No.: 150,332

57 ABSTRACT [52] A protective wrapping for an elongated member of l I 1/generally circular cross section, and particularly an 51 I t B65h 81 00abrasion resistant wrapping to protect marine cables 144 and conduits.The wrapping is a helically oriented ele- 1 2 /3? f b ment formed oflaminations preventing it from being l38l l0 125 opened outwardly andaway from the protected cable, l I but allowing the cable to flex. Thewrapping can be installed by placement crosswise on the cable and [56]References Cited winding it about the cable to seta successive turns.UNITED STATES PATENTS Clamps, or a helical filler located between turnsof 2,693,032 12/1954 Bacon 144 the element, are used to axially extendthe wrapping 1 3133;? gggggg 32x11? 13353 .19 f tafish rip up lbisLtsssabla 3:616:12? 10/1971 Reynolds et al. 161/47 5 Claims, 5 DrawingFigures PROTECTIVE WRAPPING FOR ELONGATED MEMBER BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates to aprotective wrapping for an elongated member, and more particularly tosuch a wrapping which is abrasion resistant and which allows theprotected member to flex or bend.

2. Description of the Prior Art Heretofore the protection of marine orsubmerged cable was an expensive and time consuming operation. Forexample, it is important in many applications to lay cable or conduit onthe ocean bottom over rough terrain, ledges, reefs, sharp coral and thelike, and in areas where strong currents are apt to cause appreciablemovement of the cable. In the past such cable was protected by sectionsof a cast metal sheathing. Each section was heavy, fitted with specialinterengaging clamps and brackets, and had to be installed in situ bydivers. Installation was tedious and hazardous.

Prior art metal sheathing was relatively shortlived because'of thecorrosive conditions present at the ocean bottom. Attempts were alsomade to use a wrapping of asphalt or tar saturated fibrous material,particularly on smaller cables. This improved the resistance tocorrosion, but adjacent underwater objects and crossing cables soonabraded away the wrappings, especially where underwater currents werestrong. Not only does this result in failure of the cable, which may bea telephone link of extreme importance for example, but if the protectedmember were a conduit carrying deleterious substances, the failure ofthe conduit could have a disastrous effect upon the environment.

SUMMARY According to the present invention, a protective wrapping isprovided for an elongated member of generally circular cross section,with the wrapping comprising a helically extending element adapted fordisposition about the elongated member in close-fitting relation. Thewrapping is made of elastomeric material resistant to abrasion andcorrosion, and laminated to strongly resist radially outward movement ofthe helical turns. However, the wrapping can be installed in situ, suchas by a diver working on a submerged cable, by placing the wrappingcrosswise of the cable to locate the cable between the end turns of thewrapping, and thereafter winding the body of the wrapping about thecable to place successive turns upon the cable.

In one embodiment the ends of'the wrapping are clamped, preferably afterthe wrapping is axialy extended upon the protected member, to maintain atight grip of the wrapping upon the member. In another embodiment ahelical filler is located between the turns of the first helical elementto effect the axial extension, and also to provide additional abrasionresistance, while yet still allowing flexing and bending of theprotected member.

The wrapping can be made in any length desired, provides extremeenvironmental and abrasion protection because of the tough elastomericmaterials used, allows flexing, and does not require clamping whenproperly dimensionally configured. It can be installed at the point ofmanufacture or in the field, and has wide application to the wrapping ofany elongated element, such as a tube, conduit, cable or the like, whichhas to flex somewhat and has to be cushioned or protected from wear andabuse, whether to prevent destruction of the protected member or toprotect the environment from the contents of such a member whoseintegrity has been destroyed.

Other objects and features of the invention will become apparent fromconsideration of the following description taken in connection with theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a perspective view of aprotective wrapping, according to the present invention, comprising ahelical element mounted upon an elongated member to be protected;

FIG. 2 is an enlarged view taken along the line 2-2 of FIG. ll;

FIG. 3 is a longitudinal cross sectional view of another embodiment ofthe present invention, in which a helically disposed filler is arrangedbetween the turns of the helical element of FIG. 1;

FIG. 4 is a side elevational view of the element of FIG. 1, andincluding a pair of clamping means at the element extremities toconstrain the element against axial movement; and

FIG. 5 is a perspective view of the element of FIG. 1, illustrating themanner of mounting the element upon the elongated member.

DESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference toFIG. ll of the drawings, there is illustrated a protective wrapping 10having an internal diameter such that it is disposed about an elongatedmember of generally circular cross section in close-fitting relation.For the purpose of this descriptionthe elongated member is assumed to bea marine cable 12 which is to be protected against abrasion and damagefrom underwater objects or the like.

As will be seen, the wrapping must be adapted to tightly grip itselfupon the cable 112, resisting axial movement along the cable 12, andparticularly resisting any opening movement in a radially outwarddirection which would have the effect of increasing the diameter of thewrapping and tearing it away from the cable. In addition, the wrappingmust be capable of being installed in situ by a diver working underwater, and it must permit flexing and bending movements of the protectedcable 12. In order to accomplish these purposes, the wrapping 110comprises a helically oriented element llll having a plurality ofuniformly spaced apart turns.

As will subsequently be described, the wrapping 110 is prevented fromdeforming radially outwardly by reason of its laminated construction.However, it can be deformed in a direction generally normal tothe'longitudinal axis of the element II, as illustrated in FIG. 5. Withthis arrangement, if the wrapping 10 is disposed generally transverselyof the cable 12, the cable 12 can be located between the pair of endturns and one of the end turns can then be deformed sufficiently tolocate it around the cable. The remaining turns are next wound about theperiphery of the cable 12 in succession to seat them in position. InFIG. 5 half a turn is shown held securely by engagement with the cable,while the other half turn is being deformed axially to lay it over thecable.

After the wrapping is in position upon the cable 12, axial extension ofthe wrapping 10 has the effect of reducing the internal diameter of thewrapping 10 so that the wrapping closely grips the cable 12, tending toprevent further axial movement. One method of anchoring the wrapping 10to the cable 12 is illustrated in FIG. 4, a pair of anchorage means orannular clamps 14 being utilized to prevent the wrapping from beingmoved axially. Each clamp 14 is in the form of a band disposed about anend turn, and having a pair of confronting end flanges which are clampedtogether by usual fasteners disposed through the flanges, as will beapparent. Preferably one clamp 14 is placed in position to clamp one endof the wrapping 10, the wrapping 10 axially extended, and then thesecond clamp 14 is located in position.

The laminated structure of the element 11 is illustrated in FIG. 2. Moreparticularly, the wrapping 10 includes a plurality of generallyparallel, axially oriented, and helically extending laminations ofelastomeric material in the form of rubber layers 16 which are stronglybonded together by any suitable means. The rubber may be any natural orsynthetic type, or suitable combinations thereof, and in an uncuredstate. Between these rubber layers 16 are layers 18 of high tensilestrength fabric material, such as 8 ounce woven glass fiber cloth.

In one suitable embodiment the rubber material of the layer 16 is atough, vehicle tread wear grade of urethane rubber, although othermaterials are also satisfactory if they possess corresponding highresistance to abrasion and penetration by rocks, coral, and the like,and good chemical and bio-chemical resistance to sea water. I

When utilizing uncured urethane rubber, the laminated wrapping 10 isformed by arranging alternating rubber and fabric layers 16 and 18 in asuitable mold of the desired helical form. The assembly is thensubjected to heat and pressure, as by bagging in cellophane andinsertion in an oven. This cures or vulcanizes the rubber of the layers16, causing it to become plastic and flow into the interstices of thefabric layers 18. This provides a bond between the layers 16 and 18which has been found to possess even greater tensile strength than thatof the rubber of the layers 16. The resistance of the assembly todelamination is productive of great resistance to radially outwarddeformation, as previously mentioned.

If the elastomer selected for the layers 16 is a cured natural orsynthetic rubber, or mixture thereof, the alternating fabric layers 18are utilized as before, but high strength adhesives are coated upon thefaying surfaces of the layers 16 and 18 to ensure a good bond. Thus, ifthe rubber selected is a 60 durometer cured neoprene, the surfaces ofthe layers are treated or prepared according to best current practice tobond to the adhesive used.

In this regard, catalytic cured adhesives, and particularly epoxyresins, are satisfactory. One suitable adhesive system is identified bythe trademark EPOXEY- LITE-8846 and is a product of the EpoxeyliteCorporation, South El Monte, California. This particular formulation isbased upon a diglycidyl ether bisphenol resin and has a molecular weightof approximately 380. It includes a blend of amine curing agents and adiluent to improve wetting with the glass fibers of the fabric layers18. The resin system has a relatively extended pot life of in excess ofone and one-half hours at a room temperature of F, and cures inapproximately one hour at 200F. It has excellent all around chemicalresistance, good wetting, and good adhesion to the layers 16 and 18.

In the cured rubber embodiment, the layers 16 and 18 are coated on theirfaying surfaces with the adhesive, layed up in a suitable mold of theproper helical shape, preferably with the outermost and innermost layersbeing rubber layers 16, and the whole subjected to heat to cure theadhesive.

The tensile strength of the fabric layer 18 is usually in excess ofl5,000 pounds per square inch, and the strength of the bond between thelayers 16 and 18 is preferably in excess of the tensile strength of therubber layer 16.

Although considerable dimensional variation is possible, it has beenfound that handling and installation of the wrapping 10 at the point ofuse is facilitated when the wrapping is made in sections which areabutted together. The sections are preferably four feet or less inlength.

In a typical application the cable 12 may have a diameter of 1 inch, inwhich case the thickness of each rubber layer 16 will be approximatelyone-sixteenth of an inch, the thickness of each fabric layer 18 will beapproximately one thirty-second of an inch, the glue line thicknessbetween the layers will be approximately 0.005 to 0.020 inch, and thetotal thickness of the assembly will be approximately one-half inch.

Referring now to FIG. 3, an embodiment of the invention is illustratedwhich utilizes not only the helically extending element 11, but alsoahelically extending filler 20 disposed in the space between the turns ofthe element 11 in generally coextensive relation. The filler 20 ispreferably also made of an elastomeric, abrasion resistant material suchas rubber and has sufficient flexibility that it does not prevent thedesired flexing and bending of the cable 12. A durometer valve rubber ofabout 50 to 60 has operated satisfactorily. If a less flexible, higherdurometer rubber is used, such as above 60, there is preferably formedin the filler 20 at the time of molding a pair of continuous, oppositelydisposed helically extending grooves 22 and 23, shown in dotted outlinein FIG. 3 in one turn of the filler. The grooves 22 and 23 present areduced cross section which allows limited flexing and bending of thecable 12, but which is still relatively resistant to radially outwarddeformation of the tiller, such as might cause separation of the fillerfrom the cable 12.

The thickness of the filler 20 is made about the same as that of theelement 11 so that the outer surfaces of these components are generallyflush. The installed thickness of each of these components in an axialdirection is generally the same.

The radial thickness of each turn of the element 11 reduces in an inwarddirection because both the front and rear walls of the turn slopeinwardly. Typically if the axial thickness of the outer surface werethreefourths of an inch, the axial thickness at the inner surface wouldbe approximately one-eighth of an inch less.

The configuration of the tiller 20 is complemental to that of theelement 11, being characterized by a taper in an opposite direction, sothat the axial thickness of the filler is approximately three-fourths ofan inch at its inner surface, and approximately one-eighth of an inchless at its outer surface.

The axial thickness of the filler is preferably slightly greater,approximately one-eighth of an inch, in its unstressed state. Thus,after the element 111 is located on the cable 12, the end turn of thefiller 20 is inserted between the turns of the element 111 and deformedfor wrappingupon the cable 112 in the same manner previously describedin connection with the element Ill. That is, the end turn of the filler20 is deformed to a position generally at right angles to the nominalaxis of the filler 20, and the remainder of the filler 20 is thenrotated about the longitudinal axis of the cable 112. Since the axialthickness of the filler 20 is slightly greater than the axial spacebetween the turns of the element 1 1, the filler 20 is preferablystretched or elongated while it is being installed. This reduces itscross section sufficiently to fit it into the available space. Onrelease of such tension the filler 20 expands and presses against theelement 111, axially extending the element 11 and reducing its innerdiameter so that it tightly grips the cable 12.

From the foregoing it will be apparent that the protective wrappingprovides a continuous covering or sheath for tubing or cable. It ishighly resistant to abrasion and impact, provides moderate thermalinsulation, and is installable either at the time of manufacture or onthe job site. Clamps need not be used to anchor the wrapping to thecable, particularly if the filler material is used or if the innerdiameter of the wrapping is made sufficiently small. However, clamps canbe utilized if desired.

The wrapping is easily installed without complex tooling and it hassufficient flexibility to allow normal bending or flexing of the cable.The wrapping is easily molded or otherwise fabricated in a relativelyinexpensive manner.

Various modifications and changes may be made with regard to theforegoing detailed description without departing from the spirit of theinvention. This is particularly true with respect to the dimensions setforth, since these are merely exemplary and will vary according to thedurometer or shore valve of the elastomer, and elongation and the like.

I claim:

ll. In combination with an elongated member of generally circular crosssection, a protective wrapping comprising:

a helically extending element disposed about said elongated member inclose-fitting relation, the helical turns of said element being axiallyspaced apart, said element including a plurality of generally parallel,axially oriented, and helically extending alternating laminations ofelastomeric material and fabric material bonded together whereby saidhelical turns strongly resist deformation radially outwardly in adirection effective to increase the diameter of said turns; and

a helically extending elastomeric filler having its helical turnsdisposed within the spaces between said helical turns of said element ingenerally coextensive relation, the axial width of each of said turns ofsaid elastomeric filler in its unstretched state being greater than thecorresponding axial distance between adjacent said turns of said elementwhereby said turns of said filler exert an axial bias upon said turns ofsaid element tending to move said turns of said element apart andthereby cause said element to tightly grip said elongated member.

2. A combination according to claim 11 wherein the contacting sides ofsaid turns of said filler and said turns of said element arecomplementally sloped whereby said turns of said filler tend to wedgeapart said turns of said element.

3. A combination according to claim ll wherein the direction of slope ofsaid sides of said filler and said element defines an axially widerinner portion for each of said turns of said filler, compared to theadjacent turns of said element, whereby said turns of said filler exerta bias upon said turns of said element.

41. In combination with an elongated member of generally circular crosssection, a protective wrapping comprising:

a helically extending element disposed about said elongated member insufficiently close-fitting relation that axial extension of said elementincreases the axial length of the space between the helical turns anddecreases the inner diameter of said element, whereby said elementtightly grips said elongated member, said element including a pluralityof generally parallel, axially oriented, and helically extendingalternating laminations of elastomeric material and fabric materialbonded together whereby said helical turns strongly resist deformationradially outwardly in a direction effective to increase the diameter ofsaid turns; and

an elastomeric helically extending filler having its helical turnsdisposed within the spaces between said helical turns of said element ingenerally coextensive relation, the unstretched axial thickness of saidfiller being slightly greater than the corresponding axial length of thespace between adjacent turns of said element whereby said filler in saidspace is stretched and exerts a bias upon said element whereby saidelement tightly grips said elongated member.

5. A combination according to claim 41 wherein said elastomeric materialof said element is a tough, vehicle tread wear grade of rubber and saidfabric material is

2. A combination according to claim 1 wherein the contacting sides ofsaid turns of said filler and said turns of said element arecomplementally sloped whereby said turns of said filler tend to wedgeapart said turns of said element.
 3. A combination according to claim 1wherein the direction of slope of said sides of said filler and saidelement defines an axially wider inner portion for each of said turns ofsaid filler, compared to the adjacent turns of said element, wherebysaid turns of said filler exert a bias upon said turns of said element.4. In combination with an elongated member of generally circular crosssection, a protective wrapping comprising: a helically extending elementdisposed about said elongated member in sufficiently close-fittingrelation that axial extension of said element increases the axial lengthof the space between the helical turns and decreases the inner diameterof said element, whereby said element tightly grips said elongatedmember, said element including a plurality of generally parallel,axially oriented, and helically extending alternating laminations ofelastomeric material and fabric material bonded together whereby saidhelical turns strongly resist deformation radially outwardly in adirection effective to increase the diameter of said turns; and anelastomeric helically extending filler having its helical turns disposedwithin the spaces between said helical turns of said element ingenerally coextensive relation, the unstretched axial thickness of saidfiller being slightly greater than the corresponding axial length of thespace between adjacent turns of said element whereby said filler in saidspace is stretched and exerts a bias upon said element whereby saidelement tightly grips said elongated member.
 5. A combination accordingto claim 4 wherein said elastomeric material of said element is a tough,veHicle tread wear grade of rubber and said fabric material is wovenglass cloth.